The background information is believed, at the time of the filing of this patent application, to adequately provide background information for this patent application. However, the background information may not be completely applicable to the claims as originally filed in this patent application, as amended during prosecution of this patent application, and as ultimately allowed in any patent issuing from this patent application. Therefore, any statements made relating to the background information are not intended to limit the claims in any manner and should not be interpreted as limiting the claims in any manner.
It is known to provide filter material having a relatively high efficiency rating commonly referred to as a High Efficiency Particulate Air (HEPA, 99.97% efficient at a 0.3 μm particle size) or ultra-low penetration air (ULPA, 99.999% efficient at a 0.12 μm particle size) or larger by having expanded polytetrafluoroethylene (ePTFE) incorporated within the filter material. However, the scrim or materials having an ePTFE containing filter material may lack desired properties. For example, an undesirable increase in pressure drop across the filter material may result during filtration.